PRACTICAL ORGANIC CHEMISTRY is then passed through for six to twelve hours, .and the retort occasionally weighed, until the increase in weight (50 grains) roughly corresponds to the formation of monochloracetic acicl. The operation is then stopped. The action of the chlorine is greatly facilitated by sunlight. The yellow liquid in the retort is decanted from the sulphur into a distilling flask, and distilled over wire-gauze. Some acetyl chloride, sulphur chloride, and unchanged acetic acid first distil, after which the temperature FIG. 62. rises and the fraction boiling at 150°—190° is collected separately. It is advisable to run the water out of the condenser when the temperature approaches 170°, as the acid may solidify and bloclc the condenser-tube. The distillate solidifies on cooling-. Any liquid is drained off at once, and the solid is redistilled and col- lected at i So0—190°. It is nearly pure chloracetic acid, Yield 80—100 grams. CH3.CO.OH + CIa = CH2C1.CO.OH + HC1. The sulphur acts as a "chlorine carrier" by forming sulphur chloride. Properties.—Colourless crystals ; m. p. 63°; b. p. 185°—187° ; readily soluble in water,-and deliquescent in moist air. It causes blisters on the skin. See Appendix, p. 252.